Electroencephalographic apparatus



July 5, 1955 F. F. OFFNER 2,712,309

ELECTROENCEPHALOGRAPHIC APPARATUS Filed Dec. 23, 1955 3 Sheets-Sheet l ATTORNEY` July 5, 1955 F. F. oFFNl-:R

ELECTROENCEPHALOGRAPHIC APPARATUS 3 Sheets-Sheet-'Z Filed Deo. 23, 1953 3550 49... 491D 45 49C 45ML 9' INVENTOR July 5, 1955 F. F. OFFNER 2,712,309

ELECTROENCEPHALOGRAPHIC APPARATUS Filed Dec. 25, 1955 3 Sheets-Sheet 5 m M ffw ATTORNEYS a nected to electrodes 4 and 5. The connections between the desired electrode combinations and the ampliers can thus not only be made very quickly but it is also quite evident that there is no possibility of making a mistake in the connections since all that one has todo is to select the proper card. Of coursea large number of such cards; each identied by a suitable legend, and each having a differently located set of'holescorrsponding to the desired electrode combinations, would be provided for this purpose.

For calibrating the several amplifiers, a special card, not shown, is provided. This card is provided with'two holes for each amplifier channel, one of the holes serving to connect one input to strip 15] and hence to the calibration voltage 21 and the other hole serving to connect the other input of that same amplifier to strip 15g and hence to ground. A j y Occasionally, input connections 'to' the amplifiers d'iierent from any of those selected by the set of code punched cards furnished with the apparatus may be required. For such purposes it is convenient to be able to make individual lead selections, as may be required, In' order to accomplish this, a specially constructed card 3H, Shown in Figs. 4 and 5, but drawn to a scale Smaller than Figs. 1-3, may be employed. Card 30 includes a plurality of: parallel spaced, stationary strips 31 of insulating material held in such position between transverse strips 32. 33, also of insulating material, locatedk at each end of the set of strips 31. In the spaces between tlhe'several'strips 31 are other movable Vstrips 34 each having a single hole 35. The strips 34 are slidable longitudinally ofthe strips 31 and hence when the card 30is4 slid through the, slot 28 into the housing 7 of Fig. 1, the strips 34,'which corre- Sip-dhd in number and laterai spacing to vstrips 22a-22d, may be slid longitudinally so as to bring the hole 35 in the same in registration with any of the` tongues 23 in the strip (22a-22d) with which that particular strip 34 is associated, thus enabling one to set up any desired cornbination of electrode-amplifier connection. To enable the strips 34 to be slid longitudinally, the back wall 13 of i housing 7 is also provided with a slot 35 in alignment with and identical with the front slot 23.

In place of the punchedsc'ard arrangement illustrated in Figs. l3, one may employ a'card of insulating material having parallel spaced, stripe type conductive coatings thereon corresponding to the strips 22a-22a', and which coating stripes have ear portions located in diterent positionson different cards to establish the desired connections between the di'erent electrodes and amplifiers. Such an karrangement is shown in Figs, 6 8. 4 With reference now to these views, it will be lseen that the housing for the embodiment of. Figs. 68 is similar to that shown in Figs. l-3 and hence the parts'theretnv have been assigned corresponding reference-numerals but with primes added thereto for purposes of distincton.- l

A plurality of parallel spaced, conductivev strips 40u-4tlg extend transversely in the housing 7', the strips being secured individually in place at their opposite ends to the side walls 11. Studs 41. which secure the left ends of these strips extend to the exterior of the housing and establish terminals 42 to which the electrode leads v6 are connected, the latter thus being electrically connected respectively to the conductive strips 4011;'4e. 1

Conductive strips #fili-40g are secured at their right ends by studs 43 which extend to the exterior and establish terminals 44 for connection to the source of voltage by which theamp'liers may beV calibrated. i Y Y Each of the conductive strips 40u-40g includes a plurality of longitudinally spaced cutout tongues '45 which,

21S-.shown in Fig. 7, bear against the bottom wall 9' of the housing in the absence of an electrode connection card.

Secured across the interior rear wall 13 of the Vhousing 7Aby means of conductive studs `4.6, are a plurality-of tongue-like connectors 47 which, vas will. be efihplained,v serve to connect the selected electrodes to the amplifiers.v

The electrode selector cards, one of which is shown as card A and identified by numeral 48, is made of insulating material and provide on one face thereof with a plurality of parallel spaced, stripelike conductive layers 49a- 49d applied thereto in any suitable manner such as by coating. There are as many of these conductive layers as there are'a'mpliiier inputs, and each adjacent pair sucli as 49a-49b or 49h-49d feed the differential-inputs of an amplifier. The layers m-49d are so spaced on the card that when the card is inserted in the housing'through the front slot 28 to the position shown in broken lines, the upper ends of these layers will pass under and be engaged with the connectors 47.

The coding of each card is effected by establishing ear portions 50a-50d on the conductive layers 49m-49d which extendlaterally from themain body ofthe layer "into each line of tongues 45 on strips 40a-'-40g and 'establish contact with one of those tongues depending' upon it'si location on the card. These ear portions 50a-50d correspond in function to ythe holes 29 inv card 27 and hence` determine, by their location, which electrodes will be' conductive strip 40a with conductive layer 49a, strip 40e with layer ltl'9b, strip 40e with layer 49C, and strip 40d with layer 49d. Thus electrodes 1' and 3" will be connected to the inputs` of ampliiier l and electrodes 5 and 4 will be connected to the inputs of amplifier 2.

When there is a iarge number of ampliliers, and a large number of electrodes, the number of spring contacts i. e. the tongues 23 becomes very large. Their number may bereducedby having the interconnections between the amplifiers and electrodes made in a fixed manner on nach card, and using the spring contacts or tongues toconnect only to the layers appropriate to each, amplifier inputl Vand to each electrode. Such an arrangement is illustrated in the embodiment of Figs. 912. Here each ofl the i-nsulating cards Si has a plurality of parallel spaced conductive strips SZa-SZd on one face 'and each such strip isconnected to its corresponding amplier input throughspring contacts -53a-S3d respectively; On the opposite face of the card, and at right angles to the set of strips Shi-52d, is another set of parallel -spaced conductive strips 54a-54e connected respectivelyto theelectrode leads 6 through spring contacts SSII-55e;` Strip 54f is connected to the source ofy calibration voltage 2i b v spring contact 56 and strip 54f is connected to ground by spring Contact 57.

Coding of'a particular card S1 is accomplished by piercing it at the proper strip cross-over points 58, corresponding to lthe holes 29 in the' card shown in Fig. l and inserting conductive material 59 'so that the latterwill interconnect the strips on opposite faces of the card which cross at such points. The material 59 may 'tak-c any suitable `form such as an eyelet, rivet, or drops of solder or of electrically conductive paint; Y f Y In conclusion it -is to be understood that while the embodiments-'of my invention as illustrated herein are to be preferred, various 4changes in the construction and arrangement of the components may be made without however departing from the spirit and scope of the invention as defined in the appended claims.

Moreover, while the 4present'invention 'has been dcscribed with respect to its application to the select-ive switching of lthe 'electrode elements of electroencephalographic apparatus it will be understood tha-t the Aprinciples thereof are equally applicable to other forms of biographie apparatus which include -a plurality of eleetrodeslocated at-diterent points on Athe body of a-living Iorg'anisma'nd by which the potentials at such points are to be measured.

il. In an apparatus` for amplifying Apotentials produced at a plurality of 'points in the 'ibodyof afliving organism,

5 a plurality of electrodes adapted to be secured at different locations on said body, a plurality of amplier inputs, an electrical circuit from each of said electrodes, an electrical circuit to each of said amplifier inputs and a card of insulating material cooperative with said circuits, said card including means provided thereon in accordance with a predetermined coding for establishing predetermined interconnections between said electrode circuits and said amplier input circuits.

2, In an apparatus for amplifying potentials produced at a plurality of points in the body of a living organism, a plurality of electrodes adapted to be secured at different locations on said body, a plurality of amplier inputs, a circuit selector housing, an electrical circuit from each of said electrodes into said housing, an electrical circuit from each of said amplifier inputs into said housing, and a card of insulating material insertable into said housing and which is cooperative with said circuits, said card including means thereon provided in accordance with a predetermined coding for establishing predetermined interconnections between said electrode circuits and said amplifier input circuits.

3. In an apparatus for selectively amplifying potentials produced at a plurality of points in the body of a living organism, a plurality of electrodes adapted to be secured at different locations on said body, a plurality of amplifier inputs, and means for selectively connecting said electrodes with said amplifier inputs comprising a first set of spaced lines of contact means electrically connected respectively to said electrodes, a second set of spaced lines of contact means crossing the lines of contact means of said first set and being electrically connected respectively to said amplifier inputs, and a card of insulating material insertable between said sets of contact means, said card including means located thereon at the crossing points of certain of said lines of Contact means according to a predetermined code for establishing a connection at such points between certain contact means of said first and second sets and preventing a similar connection at all other crossing points.

4. Apparatus for selectively amplifying potentials as defined in claim 3 wherein the lines of contact means of said first and second sets are normally connected with each other at the crossing points thereof and said cardserves to disconnect the same at all crossing points except those selected by the card coding.

5. Apparatus for selectively amplifying potentials as defined in claim 3 wherein the card coding consists of apertures in said card coincident with the selected crossing points and through which the electrical connection is made between the selected contact means of said first and second sets.

6. Apparatus as defined in claim 3 and wherein said iirst set of spaced lines of contact means includes other lines of contact means connected to a source of calibratien voltage.

7. In an apparatus for amplifying potentials produced at a plurality of points in the body of a living organism, a plurality of electrodes adapted to be secured at different locations on said body, a plurality of amplifier inputs, and means for selectively connecting said electrodes with said amplifier inputs comprising a first set of spaced conductive strips electrically connected respectively to said electrodes, a second set of spaced conductive strips crossing the strips of said first set, the strips of said second set being electrically connected respectively to said ampliiier inputs, each vof the strips of one of said sets including a plurality of longitudinally spaced contact means disposed respectively at the crossing points with the strips of the other set for engagement respectively therewith, and a card of insulating material insertable between said contact means and the strips of said other set, said card having a plurality of holes located therein at certain of said crossing points according to a predetermined code and through which holes the correspondingly located contact means extend and engage the strips of said other set, the remainder of said contact means being held out of engagement with the strips of said other set by said card.

8. ln an apparatus for selectively amplifying potentials produced at a plurality of points in the body of a living organism, a plurality of electrodes adapted to be secured at different locations on said body, a plurality of amplifier inputs, and means for selectively connecting said electrodes with said amplifier inputs comprising a first set of lines of contact means electrically connected respectively to said electrodes, a second set of spaced lines of contact means crossing the lines of contact means of said first set and being electrically connected respectively to said amplilier inputs, and a card of insulating material insertable between said sets of contact means, said card including portions thereof coincident with the lines of contact means of one set and movable individually along said lines across the lines of contact means of the other set and which include means for establishing a connection between selected lines of contact means of both sets.

9. Apparatus for selectively amplifying potentials as defined in claim 8 wherein the movable portions of said card each include an aperture through which the connection is made between the selected lines of contact means of both sets.

10. In an apparatus for selectively amplifying potentials produced at a plurality of points in the rbody of a living organism, a plurality of electrodes adapted to be secured at different locations on said body, a plurality of amplifier inputs, and means for selectively connecting said electrodes with said amplifier inputs comprising a set of lines of contact means connected respectively to said electrodes, and a card of insulating material cooperative with said contact means, said card having spaced stripes of conductive material thereon, said stripes having laterally extending ear portions located thereon according to a predetermined code of connections for electrically connecting said ear portions respectively with certain of said lines Yof vcontact means and said stripes being electrically connected respectively with said amplifier inputs.

ll. Apparatus for selectively amplifying potentials as delined in claim l0 wherein each said line of contact means is constituted by a strip of conductive material having a plurality of longitudinally spaced tongues adapted to register with the ear portions of the conductive stripes on said card and which further includes other contact means connected respectively to said amplifier inputs and which engage said stripes.

12. Apparatus as defined in claim l() and wherein said set of spaced lines of contact means includes other lines of contact means connected to a source of calibration voltage.

References Cited in the file of this patent UNITED STATES PATENTS 2,647,508 Pelavin Aug. 4, 1953 

